Fuse



Nov. 7, 1944. T. B. DOE ErAL FUSE Filed Aug. 8, 1940 2 Sheets-Sheet l 25 m 3 n mmm ou ,.hmv

INVENTORS ThomasBJoefva P. Ross BY v Zen; wmf.

ATTORNEY Nov. '.7, 1944. 1'. B. DOE Erm.

FUSE

Filed Aug'. 8, 1940 2 SheetS--Sheekl 2 Md H l Z a 5 2 2 2 INVENTORS b P Ross Thomaseg, E LLzIo ATTORNEY Patented Nov. 7, 1944 UNITED STATES PATENT OFFICE FUSE Thomas B. Doe, New York, and Elliott P. Ross,

Forest Hills, N. Y., assignors to Ford Instrument p Company, Inc., Long Island City,V N. Y.; a corl i' e poration of New York Y Application August 8, 1940, Serial No. 351,896

4 Claims.

This invention relates to fuses for projectiles and more particularly to fuses for detonating a projectile at a predetermined point in its night.

An object of the invention is to provide a fuse for a projectile which functions upon the projectile being retarded to a velocity corresponding to the predetermined point in its iiight.

Another object of the invention is to provide such a fuse for a projectile in which a predetermined difference between the air pressure on the nose of the fuse due to its velocity and an air pressure set in a sealed chamber within the fuse causes the fuse to function,

Another object of the invention is to provide a fuse for a projectile in which the firing pin or hammer which is held in an inoperative condition until the projectile has reached a predetermined point in its flight is released when the set air pressure predominates by a predetermined Value.

Other objects of the invention will be apparent from a consideration of the specification and drawings in which:

Fig. 1 is a vertical `cross-sectional View of an embodiment of the invention showing the relation of parts before the fuse is set for the selected range; and

Fig. 2 is a view similar to Fig. 1 except showing the relation of parts as the fuse is about to function.

Fig. 3 is a View similar to Fig. 1 but showing a modification of the embodiment of the invention.

In many of the fuses in use heretofore a powder train leading from a firing cap to the detonating charge in the projectile is ignited at the time the projectile is fired and burns to the detonating charge of the projectile in an interval of time depending on the point oi ignition of the powder train. These fuses not only require that there be placed in the fuse itself a considerable amount of powder, which must be manufactured with great care that the rate of propagation of the flame be known and constant, but their construction has been such that they also require that the powder train be assembled with the fuse at the factory, with the attending dangers during assembly, shipment and storage.

To overcome these disadvantages, the present invention provides a fuse which may be manufactured, shipped and stored without any powder or detonating caps therein. The loading of the fuse with powder and the insertion of the firing caps are such simple operations that they may be done just before securing the fuse on the projectile.

The fuse of the present invention is iired by a firing pin or firing hammer which is moved by centrifugal force due to rotation of the projectile, acting upon the hammer mass, the hammer being held in a iixed position by a detent until the desired time of detonation. This detent is pulled out of engagement with the hammer when the projectile has reached a selected point in its night.

It is well known that the air pressure on the nose of a projectile varies with the velocity of the projectile and the conditions of the atmosphere through whichl'it passes and that the velocity of the projectile varies with the time of flight and the angle of elevation until the projectile has reached its maximum height in the trajectory. Data for the various sizes of projectile and initial velocities are well known and are available in easily interpretable tables and curves.

To release the detent there is provided an opening in the nose of the fuse which is placed in communication with one side of a diaphragm when the projectile is red. The other side of the diaphragm is in communication with an air chamber in the fuse in which has been sealed air at a `predetermined pressure. The `detent is Acorinected to the diaphragm and releases the firing hammer when the nose air pressure has been reduced `to an amount such that the diaphragm is moved under vthe pressure of the air in the sealed chamber. The required pressure in the sealed chamber is determined by' the range at which it is desired that the projectile be detonated and the diierence i-n pressure on the two sides of the dia@ phragm that is necessary to snap it over from one position to another. With the type of diaphragm used in one construction, a diiierence of pressure of ten pounds per square inch was necessary to snap over the diaphragm from one positionto another. Thus, Vif it is desired to detonate the 'projectile at a range Ahaving a corresponding nose pressure of seventy-live pounds per square inch, the sealed air chamber Ywould be charged to a pressure of eighty-nteV poundsper square inch.

It will therefore be seen that when the projectile has reached the desired range', 'the diaphragm will be snapped over and the'iiring hammer will be released from its restrained position. The hammer will then move outward against one of `the firing capsV under the laction of centrifugal force Acreated by the rotation of the shell aboutits centra-l axis.

come the disadvantages inherent in these pre-` viously disclosed arrangements.

Referring to the drawings and particularly to Fig. 1, I represents the conical walls of the fuse secured to the lower part of the core 2 by screw threads 3. The lower portion of core'2, base 4, is adapted to be screwed'into the nose of the projectile. The upper portion of the core member 5, is adapted to be screwed into the nose of the conical walls of the fuse such that the bore 6 of member 5 is aligned with an opening 'I in the nose of the fuse. v .l n

In the base 4 is formed a transverse cylin-v drical cavity 8 at each end of which are firing caps 9 held in position by screw plugs I0 which abut against the shoulders II at the ends of cavityv 8. Screw plugs IIJ have passageways I2 for ignition powder I3, which is in contact with firing caps 9 and the ignition powder in passageways I4 and I5 leading to the lower face of l base 4. Passageway I5 is in communication with the detonating charge of the projectile (not shown) Firingcaps 9, screw plugs IU, and ignition powder I3 may be placed in position just before the fuse is mounted on the` projectile.

In cavity 8 is a double ended'ring pin or fir-` ing hammer I6 which is acted upon by centrifugal force when the projectile is in flight due to its rotation about its longitudinal axis. Hammer I6 is held in its central position by detent I'I engaging shoulders I8 on hammer- I6. yDetent I'I slides into and out of engagement' with hammer I6 with the movement of l diaphragm I9 towhich it is attached by shouldered stud 23. 'I'he stud Eil is secured to the diaphragm `by a riveted or soldered head 2I. Diaphragm I9 is secured to outward extending flange portion 22 of core 2. The upwardly extendingr portion of diaphragm I9 and the outer vertical sides of flange 22 form with the walls I a passageway 23 in communication with chamber 24, formed by the Walls I, the outer surface of memberv 5 and the upper surface of flange 22. end of ,passageway 23 is in communication with space 25 under the diaphragm I9, which space is in communication with cavity 8 by passageways 26. Cavity 8 is placed in communication with space 25 and chamber 24 to avoid the necessity of making detent Il airtight as to cavity 8.

It is preferable to allow a slight clearance for the detent Il between the shoulder on the stud and the diaphragm I9 to allow the diaphragm to move slightly under its differential pressure before having to overcome the static resistance to movement of detent Il in base Il. It has been found that with such clearance the operation of the diaphragm under the ldifferential pressure on the two sides thereof ygives a more uniform operation of the diaphragm.

The upper portion of core 2, member 5, with its flange 22 is hollow, with bore 6 at its upper end and reduced bore 2'I.at its lower end, terminating in a port 28 in communication with chamber 29. Chamber 29 is formed by one side of the dia- The lowery -it tightly withinthe bore. Pin 32 engages the y slot in cylinder 33 and acts as a guide to assure in the form of a hollow cylindrical shapedy that the slot is always out of alignment with port 3I. f

In thenlowerportion of bore 6 is a hollow stopl 34 which limits the downward movement of rvalve 33 and the upward movement of an arming inertia member to be described hereinafter. Stop 34 is held in position against th'e shoulder formed where bores t andIZ'I-meet by a drive t. The inertia member 35 terminates in a pointed piercing pin 36.A The member 35 is held from downward movement by spring 3l which engages the lower end of bore 21 and the lower face of member 35. Spring y3l is made stiff enoughA to hold the piercing-pin v36 out of contact with disk 3D during shipment and handling of the fuse, but weakvenough to permit member 35 and pin 36 to move down onto and pierce the disk 30 under the influence of its inertia when the projectile is fired. Passages 3B are drilled in member 35 and pin 36 to permit free movement ofthe member and to place bore t in communication with chamber 29 after disk 33 has been pierced.

n In the modication shown in Fig. 3 the construction is the same as that illustrated in Figs. l and 2J except that member 5 is enlarged at its lower end, as at 39, to provide lmetal for pas- Y sageway 40, which is in communication rwith `chamber 29 at its lower end and in communication at its upper end with bore 6 by port 4I. Port Il is located directly below port 3l in the walls of, member 5 so that the split cylinder 33 may control both ports; y

Operation Before ring the projectile, chamber 24 is charged rwith air through bore-Il and port 3| to a pressure greater thanthe pressure on the nose of the fuse due to velocity at the point of the trajectory of the projectile at which it is desired to fire the fuse. Split `cylinder 33 is then forced down to close theport 3l asindicated in Fig. 2,

thus effectively sealing chamber 24. As previously mentioned the pressure in chamber 24 may conveniently be ten pounds greater than the nose pressure for the point in the trajection at which l, it is desired the fuse to act.

When the projectileis red, theinertia` of member 35 overcomes the vtension of springv 31 and theA pin 36 pierces disk 30 as shown in Fig.

2. When the projectile is no longer being ac-v celerated by the ypowder chargev of the gun, spring 31 forces member 35 back to its original position, as shown in-Fig. 1, and chamber 29 is in communicationwith opening I through the hole pierced in disk 30, port 28, passages 38 and bores 21 and 6, as shown in Fig. 2.

When the projectile has reached a point in its trajectory such that the nose pressure has decreased belowthat of the air pressure in chamber 24 by say, ten pounds, diaphragm I9 snaps over to the position indicated in Fig. 2, drawing detent I1 with it and out of engagement with the shoulders I 8 of hammer I6. Hammer I6 is then free to be moved under the action of cen- 'triiiugal force to one end of cavity 8 where it strikes and sets oi one of the iiring caps 9. Firing cap 9 ignites the powder I3 which tburns through passageways I4 and I5 leading to the detonating charge in the projectile.

The operation of the modification shown in Fig. 3 is the same as for the mechanism shown in Fig. l, except that the chamber 29 is not charged with air at the time of the assembly of the fuse, but is charged at the same time and to the same pressure as chamber 24 by connecting bore 6 with a suitable source of compressed air. During the charging of the chambers 24 and 29 the split cylinder valve 33 is in the position shown in Fig. 3. Chambers 29 and 24 are charged to a pressure say, ten pounds greater than the ai'r pressure on the nose of the fuse at the point. at which it is desired to detonate the projectile. Split cylinder valve 33 is then forced down to the position indicated in Fig. 2 thus sealing ports 3I and 4I. When the projectile is red, pin 36 moves downward, due to inertia of member 35, and pierces disk 39 thereby connecting chamber 29 with port 28, passages 38, bores 21 and 6 and to the opening 1 on the nose of the fuse. The pressure in chamber 29 immediately increases due to the initial nose pressure and then decreases till the nose pressure is reduced sufciently below the pressure set in chamber 24 and space 25 to cause diaphragm I9 to snap over into the position shown by dotted lines in Fig. 3; Detent I1 is thus disengaged from hammer I6, and the fuse fired as previously described.

It will be understood that various modifications and changes in proportion and arrangement of the several elements constituting the invention may be made by those skilled in the art, without departing from the nature and scope of the invention, as defined in the appended claims.

We claim:

1. In a fuse for projectiles, the combination of a core and a diaphragm therein, an air chamber formed in part by one side of the diaphragm, a pierceable disk, a, second air chamber formed in part by the other side of the diaphragm and one side of the pierceable disk, an opening in the nose of the fuse, a passage in the core adapted to place said opening in communication with the other side of the disk, a port in the passage in communication with the rst mentioned airchamber, a second port in the passage in communication with the second air chamber, valve means for controlling the flow of air in the ports and means for piercing the disk upon the firing of the projectile.

2. In a fuse for projectiles, the combination of a core and a ring hammer slidable therein, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a fixed position, an air chamber charged to a predetermined pressure and in communication with one side of the diaphragm, a pierceable disk, a

second air chamber charged to a predetermined pressure and formed in part by the second side of the diaphragm and one side of the pierceable disk, an opening in the nose of the fuse, a passage in the core adapted to place said opening in communication with the other side of the disk, and means for piercing the disk upon the firing of the projectile whereby the second side of the diaphragm is exposed to the air pressure on the nose of the projectile and the diaphragm moves to disengage the detent from the hammer when the nose air pressure has decreased to a predetermined pressure.

3. In a fuse for projectiles, the combination of a core and a firing hammer slidable therein, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a ixed position, an air chamber formed in part by one side o the diaphragm, a pierceable disk, a second air chamber formed in part by the second side of the diaphragm and one side of the pierceable disk, an opening in the nose of the fuse, a passage in the core adapted to place said opening in communication with the other side of the disk, ports between the passage and the chambers, valve means for controlling the ports, and means for piercing the disk upon the firing of the projectile whereby the second side of the diaphragm is exposed to the air pressure on the nose of the projectile and the diaphragm moves to disengage the detent from the hammer when the nose air pressure has decreased to a predetermined pressure.

4. In a fuse for projectiles, the combination of a core and a ring hammer slidable therein, a diaphragm in the core, a detent connected to the diaphragm for holding the hammer in a fixed position, an air chamber formed in part by one side of the diaphragm, a pierceable disk, a second air chamber formed in part by the second side of the diaphragm and one side of the pierceable disk, an opening in the nose of the fuse, a. passage in the core adapted to place said opening in communication with the other side of the disk, ports between the passage and the chambers, valve means for controlling the ports, a pin operable by inertia upon the ring of the projectile for piercing the disk whereby the second side of the diaphragm is exposed to the air pressure on the nose of the projectile and movement of the diaphragm disengages the detent from the hammer when the nose air pressure has decreased to a predetermined pressure.

THOMAS B. DOE. ELLIOTT P. ROSS. 

